C语言实现 两个单调递增单向链表的合并

合并的主要函数与归并排序中的Merge思想一致

核心代码如下：

void Merge(LNode *&A,LNode *&B,LNode *&C){
	if(A == nullptr || B == nullptr)
		return;
		
	C = A;//将A的头结点直接作为C的头结点
	 
	LNode *p = A->next;
	LNode *q = B->next;
	LNode *r = C;
	free(B);//将B的头直接释放
	B = nullptr;
	A = nullptr;
	
	while(p != nullptr && q != nullptr){
		if(p->data <= q->data)
		{
			r->next = p;
			p = p->next;
			r = r->next;
		} 
		else
		{
			r->next = q;
			q = q->next;
			r = r->next;
		} 
	} 
	
	r->next = nullptr;
	
	if(p!=nullptr)
		r->next = p;
	else
		r->next = q;
	
}

完整实现代码如下:

#include<stdio.h>
#include<malloc.h>
using namespace std;

typedef struct LNode{
	int data;
	struct LNode *next;
}LNode;

void CreatelistR(LNode *&head,int arr[],int n);//尾插法创建带头结点的单向链表 
void CreatelistF(LNode *&head,int arr[],int n);//头插法创建带头结点的单向链表 

void Merge(LNode *&A,LNode *&B,LNode *&C); 
void ShowList(LNode *head);

int main(){
	LNode *head = nullptr;
	int arr[] = {7,9,12,16,18,23,26,28,35,38,40,58};
	CreatelistR(head,arr,sizeof(arr)/sizeof(arr[0]));
	ShowList(head);
	
	LNode *head_2 = nullptr;
	int arr_2[] = {12,14,23,26,29,35,37,39,46,70};
	CreatelistR(head_2,arr_2,sizeof(arr_2)/sizeof(arr_2[0]));
	ShowList(head_2);
	
	LNode *head_3 = nullptr;
	Merge(head,head_2,head_3);
	ShowList(head);//已为空 
	ShowList(head_2);//已为空 
	ShowList(head_3);	
	
	return 0;
}

void Merge(LNode *&A,LNode *&B,LNode *&C){
	if(A == nullptr || B == nullptr)
		return;
		
	C = A;//将A的头结点直接作为C的头结点
	 
	LNode *p = A->next;
	LNode *q = B->next;
	LNode *r = C;
	free(B);//将B的头直接释放
	B = nullptr;
	A = nullptr;
	
	while(p != nullptr && q != nullptr){
		if(p->data <= q->data)
		{
			r->next = p;
			p = p->next;
			r = r->next;
		} 
		else
		{
			r->next = q;
			q = q->next;
			r = r->next;
		} 
	} 
	
	r->next = nullptr;
	
	if(p!=nullptr)
		r->next = p;
	else
		r->next = q;
	
}

void CreatelistR(LNode *&head,int arr[],int n)//尾插法 
{
	if(arr == nullptr || n < 0)
		return;
	head = (LNode *)malloc(sizeof(LNode));
	head->next = nullptr;
	
	LNode *temp = head;
	for(int i=0;i<n;i++)
	{
		LNode *node = (LNode *)malloc(sizeof(LNode));
		node->data = arr[i];
		node->next = nullptr;
		
		temp->next = node;
		temp = temp->next;	
	}
} 

void CreatelistF(LNode *&head,int arr[],int n){//头插法 
	if(arr == nullptr || n < 0)
		return;
	head = (LNode *)malloc(sizeof(LNode));
	head->next = nullptr;
	
	LNode *temp = head;
	for(int i=0;i<n;i++)
	{
		LNode *node = (LNode *)malloc(sizeof(LNode));
		node->data = arr[i];
		
		node->next = temp->next;
		temp->next = node;	
	}
} 

void ShowList(LNode *head){
	if(head == nullptr)
		return;
	while(head->next != nullptr)
	{
		printf("%d ",head->next->data);
		head = head->next;
	}
	puts("");
	puts("");
}

运行结果如下: